Source for poly(ribothymidine) aka poly(5-methyluridine)

im trying to locate a source for any of the following:
1. poly(ribothymidine) which is the same as poly(5-methyluridine)
2. an oligomer of the above
3. the diphosphate of ribothymidine for use in TdT synthesis
4. the phosphoramidite for use in solid-phase synthesis
thanks